How are waterfalls formed?
Waterfalls are formed when a water source, such as a river, flows off a cliff into a pool of water below. The water erodes the soft rock behind the water when it smashes into it. Over a period of time (not possibly in your lifetime) the soft rock collaspes and forms a plunge pool, where the water is collected. Water from the stream carries pebbles, stones and boulders down-stream The water continues to erode the soft rock. This process is called undercutting. After another set period of time, the hard rock above collapses due to it being supported by nothing. The water source then retreats back further inland. This process then repeats over and over again. Now we might have famous waterfalls like Angel Falls and Niagara Falls, but next time, they will cease to exist. When the water retreats further inland, the distance from the water source to the waterfall will get closer. Eventually, there wouldn't be a waterfall, just a river.
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1. Angel Falls in Venuzuela.
2. Niagara Falls in between the border of Canada and U.S.A. 3. Victoria Falls in Zambia. |
Information taken from
http://geography.howstuffworks.com/terms-and-associations/waterfall1.htm
http://geography.howstuffworks.com/terms-and-associations/waterfall1.htm